how to pass variables in aws cli command (json) ?

I want to run aws cli command , in say amazon provided linux container, not sure if it comes with the aws cli , but probably can do a pip install. I understand , there is a short hand and json version of the aws cli, say for example, we have command below , i would like to declare a variable , say Table_Name = 'some_table' and pass that in the command below. how do i do that , so the command would be => aws dynamdb update-table ....--table-name $Table_Name

aws dynamodb update-table \
    --provisioned-throughput '{"ReadCapacityUnits":15,"WriteCapacityUnits":10}' \
    --table-name MyDDBTable